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How to Grow Geraniums: The Complete Geranium Flower Guide

Pink Pelargonium flowers
Photo Credit
aniana/Shutterstock
Botanical Name
Pelargonium spp.
Plant Type
Flower
Sun Exposure
Full Sun
Bloom Time
Spring
Summer
Flower Color
Multicolor
Pink
Purple
Red
White
Hardiness Zone
10
11

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Planting, Growing, and Caring for Geraniums

Catherine Boeckmann
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Pelargonium (aka common geraniums) are colorful summer-flowering plants popular for hanging baskets, pots, and garden beds. Drought- and heat-tolerant, these tender annuals can bloom all summer from June through fall frost! See how to grow and care for pelargonium.

Note: Despite being commonly called “geraniums,” pelargoniums are not true geraniums that belong to a separate genus (Geranium) which are cold-hardy perennials. The guide below is about growing the “common geranium” (genus Pelargonium), which is the tender annual most of us know and love.

Geranium or Pelargonium? A Case of Mistaken Identity

The popular plant that most of us call “geraniums” today was introduced to Europe by Dutch traders who brought them from South Africa in the early 18th century. Because these new plants resembled the hardy wild geraniums already growing in Europe, botanists mistakenly grouped them together into the same genus.

In 1753, Swedish botanist Carl Linnaeus classified them under the genus Geranium. When it was later discovered that these new “geraniums” differed from European geraniums in the shape of their petals, the number of stamens, and other factors, they were reclassified under Pelargonium, meaning “stork’s bill”—a reference to the long, sharply pointed shape of their seedpod.

However, their original common name stuck, and we still say “geranium” when we actually mean “pelargonium.” Perhaps it’s just hard to say pelargonium! This word is pronounced “Pel-ar-GO-knee-um.”

About Pelargoniums

Pelargonium, aka common geraniums, are small- to medium-sized herbaceous annuals in North America. Because they can bloom so nicely all summer (through frost), these flowering plants are often used in planters and window boxes, but they’re also used as bedding plants along foundations, paths, and entrances.

The common geranium comes in a wide range of floral colors (red, orange, pink, white) in single or double flowers set high above lush, green leaves, sometimes bi-colored with bronze or purple markings. Once mature, most geraniums are 12” to 18” tall and 18” to 24” wide, depending upon the cultivar.

Many cultivars, such as ivy-leaved pelargoniums, are trailing types that look wonderful in hanging baskets. There are also scented geraniums that are aromatic when the leaves are rubbed! Then, there are upright pelargoniums which are bushy with attractive foliage which look great in bedding displays. 

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Planting

Pelargonium, aka common geranium, is a sun lover. It requires 5 hours of sun per day. It doesn’t require as much watering as many annuals, but it does prefer moist, well-drained soil. 

Often grown in pots or as container plants, they can be kept outside until fall frost dates in a partly sunny to sunny location. This annual will die with several frosts or the first hard freeze.

When to Plant Pelargonium

As sun-lovers, pelargonium should not be put outside until nighttime temperatures are regularly above 55°F (13°C). Then, in late summer, when nighttime temperatures start to dip under this temperature, bring them inside.

How to Plant Pelargonium

When buying geraniums from the garden store, pay close attention to color and size. Healthy leaves will have no discoloration on or below them, and the stems will be sturdy, not straggly. Be sure to avoid any plants with obvious signs of pests as well. 

Place plants in large pots with drainage holes to avoid root rot. To allow for root spread, plant one plant (possibly two plants) in a large pot (at least 12” in diameter).

When planting in containers, use an excellent, well-draining potting mixture (not heavy soil). Geraniums do not like to sit in soggy or compacted soil.

Avoid planting too densely in the ground so the plants have plenty of air circulation. Allowing any geranium variety to have generous root growing space is very important; they will deteriorate without growing space. Also, to avoid pests, practice crop rotation and do not keep planting pelargonium in the same place every year. 

Growing

How to Care for Geraniums

  • If planting in the ground, add a light mulch to cover the soil to cool the root zone.
  • Allow soil to dry to some extent between waterings, then water thoroughly. Over-moist soil does more damage than under-watering. Do the finger poke; if it’s dry at 1-inch depth, then water. Do not water from overhead nor splash the foliage when watering, or you’ll invite disease. 
  • Deadheading is important for continuous bloom throughout the summer. Deadhead all spent blooms. Also, deadhead after heavy bloom or a strong rain. One reader shared a tip, “For continued reblooming, finger pinch just below the spent flower as much as possible. I did, and each of my pelargoniums bloomed from spring into fall year after year. 
  • To promote bushiness and curtail legginess, pinch back the stems. 
  • During active growing months, fertilize every 2 weeks or so. Use a water-soluble fertilizer at half-strength. Don’t fertilize in winter, when the plant should be dormant.
  • If you’re bringing in the plant for winter, water much less, but do not let the roots dry out entirely. Geraniums do best when given a period of dormancy through the winter months, during which they use less water and do not grow much. See below for more overwintering instructions.
  • Geraniums can be repotted in spring to encourage new growth—or, if they need to be refreshed.

red and white Geranium flowers

Overwintering Geraniums

  • Geraniums that have spent the summer outdoors can be kept as houseplants, provided they get lots of sun. In northern climes, the sun may not be strong enough in late winter to stimulate buds on some varieties.
  • Before the first fall frost, lift the plants and, using a sharp, clean knife, cut the stems back in a shapely fashion to about 6 to 8 inches. They should not have to support great masses of leaves in the low-sunlight environment they are about to enter. Save a few stems as cuttings to root—an easy way to multiply your plants.
  • Transplant the “mother plant” to the smallest pot possible—enough to just fit the roots—using regular potting soil to fill.
  • Keep the plants in the shade for a week, then place them in a sunny spot (they need all the sun they can get) and keep them cool.
  • During winter, geraniums grow best with night temperatures of 50° to 60°F (10° to 16°C) but will survive if they drop to 32°F (0°C) and/or rise above 80°F (27°C), as long as they are kept relatively dry.
  • When new growth appears in the spring, cut off all the old leaves.

The only thing more difficult than achieving new growth is keeping it. And here’s some help with that:

  • Water is only available when the leaves show signs of drooping, and only small amounts are provided. Do not fertilize or feed the plants. It is critical that these plants get rest.
  • If you want your overwintered geraniums to bloom for Memorial Day, pinch them back in February. Once warm weather returns and all danger of frost has passed, take the plants outdoors and transplant them to beds or pots, as you wish.

Types

  • Interspecific: zonal and ivy hybrids; nonstop flower producers
  • Ivy (Pelargonium peltatum): named for a trailing habit and ivy-like foliage; single, semidouble, or double flowers; colors include bicolor, burgundy, pink, purple, red, salmon, and white. Very popular for hanging baskets, window boxes, and containers. 
  • Regal, aka ‘Martha Washington’ (P. x domesticum): bicolor burgundy, lavender, pink, and white blooms; fussy—prefers cool, wet, climate conditions to hot, humid, and/or sunny; inappropriate conditions will reduce flower production; often a houseplant
  • Scented: foliage yields scent (cedar, lemon, lime, mint, orange, and rose) when brushed or rubbed; note that ‘Citronella’ does not repel mosquitoes; pink or white flowers are smaller than those of zonals. It can be addictive to collect them all. Learn more about scented geraniums.
  • Seed: similar to zonals; propagated by seeds; slower-growing, shorter, more compact than zonals; smaller but more numerous flowers than zonals; flowers “shatter” (are shed naturally)
  • Variegated: a form of zonal; bi- or tricolor foliage; tends to have fewer flowers than other zonal types
  • Zonal (P. x hortorum): the most common form; “zonal” refers to patterns on the leaves that darken with maturity; propagated by cuttings; single or double flowers; colors include bicolor, orange, purple, red, salmon, and white. These thrive in containers (as well as outdoors).

Harvesting

How to Root Geranium Stem Cuttings

Most geraniums root VERY easily from stem cuttings in soil, coarse sand, water, perlite, or other rooting material.

  1. Using a sharp, clean knife, make a slanted cut 4 inches below a stem tip, above a node where leaves emerge. Trim the cutting to just below a node. Remove any buds, all but two or three leaves, and the leaflike stipules at the base of leaf stalks.
  2. Roll the stem cutting in a newspaper or put it in the shade for 24 hours so the cut end will seal and not rot.
  3. Push the stem into a pot of moistened rooting medium and store it in a warm, shady place for 2 days. After that, give the cutting some indirect sun. Moisten the medium only as needed.
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Wit and Wisdom

  • For minor cuts, apply crushed geranium leaves to stop the bleeding.
  • In the language of flowers, scarlet geranium means silliness. Find out more flower meanings here.
  • Geraniums are known to be toxic to Japanese beetles, so you won’t have to worry about those pesky pests. As companion plants to cabbages, corn, peppers, roses, and tomatoes, pelargoniums repel cabbage worms and Japanese beetles.
  • Geraniums may cause indigestion or vomiting in young children and pets (cats, dogs), so keep the plants out of reach of curious pets and children.
  • “Pelargonium” derives from the ancient Greek word pelargos for stork, while “Geranium” comes from the Greek word geranos, for crane; the fruit of both resemble a bird’s beak.

Pests/Diseases

  • Diseases and pests are usually not severe in outdoor situations but it can happen if you continually splash water on the foliage or there are rainy periods which can affect mass plantings. 
  • In hot weather, you may see brown leaf tips. Yellow leaves mean you are over- or under-watering.
  • Indoors, common houseplant pests include mealybugs, whiteflies, and spider mites. 
Flowers
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
 

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Comments

Carol (not verified)

1 month 2 weeks ago

I have been growing geranium in pots for years, cutting way back and bringing indoors in the fall. This year, they were beautiful through July. Now, something is eating lacy holes on leaves and buds dying on some, and yellowing leaves on others. I don’t see any bugs or caterpillars on the leaves. What to use to spray? Can I still overwinter?

Hi Carol,

It sounds like there could be a number of pest or disease issues going on with your geraniums, and it could be more than one thing based off the symptoms you listed. While it is great that you have been bringing them in each fall for the winter, it might be time to consider getting new plants at this point considering what has happened this year.

If you truly want to save these specific plants, you could try cutting them all the way back and repotting in new potting mix, removing as much of the old mix as possible in an effort to avoid bringing anything indoors for the winter. You will still run the risk of introducing a disease or pest into your home, and if you have a lot of other plants indoors, it might not be the best idea.

Susan Harn (not verified)

5 months ago

I have never had this problem before with my geraniums. The leaves are turning brown around the outer edges. They are healthy plants and are blooming wonderfully, but I'm concerned about the browning on the outer edges of the leaves. I've never had a problem with over watering them.. They are sitting in pots on my front porch--- the same warm sunny spot they were in last year. Can you tell me what the problem might be?
Thank you!

Hi, Susan. We wonder if you are in any of the areas of the country that are experiencing record high heat at the moment. Geraniums will suffer, and leaves may turn brown, when the heat gets to be too much for them. If the browning is mostly on the lower leaves, this could mean a bacterial disease. The brown leaves could also be from over-fertilizing. 

Donna Woodman (not verified)

1 year 6 months ago

How can I keep the squirrels from digging in my geraniums?

I use garlic powder. You can buy a large bag (5 Lbs?) from Amazon. It is cheaper in bulk, a lot better than those little bottles you buy for the kitchen. Squirrels do not like the smell. I can't shoot them because they seldom come above ground until the weather warms. They eat the roots of my plants, mostly Hollyhocks. I have desert ground squirrels (I think) that are about the size of a chipmunk. They could be gophers the way they tunnel everywhere, even in the hard desert soil between my raised beds.

LYNN BROMAN (not verified)

1 year 6 months ago

20 gallon pot!!!! That's about the size of garbage can. Even 20 L is large for geranium.